Commodore - AV connector description and example cables for Audio/Video connections (C64, C128 and 264 series)

  Basic knowledge for those who want to connect their equipment to TVs/monitors via an AV connector.

I will show how to make various AV (Audio-Video) cables for the C64/C128 (40-column for the C128) and the 264 series (i.e. C16/C116/+4).

The information contained here is for the less well-informed and not for the 'professional'.

The AV DIN8U connector of the C64/C128 and 264 series computers, contains the following signals:

• Luminance (S-Video Y signal/Luma) [Luminance - pixel brightness information only, monochrome signal (e.g. for Neptune 156)];
• Chrominance (S-Video C signal/Chroma) [Chrominance - colour information, complementary to the Luminance signal];
• Composite Video [Composite video signal, pixel brightness and colour together];
• Audio Out [Output for audio from SID];
• Audio In (max 3 volts) [Audio input for SID, not used much];
• Ground (GND) / Shield [Ground, 0V];
• +5 Volt DC [Supply voltage for external devices].

Each cable described below has audio out, in the form of 2 RCA plugs (Chinch), for the left (white) and right (red) channels and ground (GND), possibly the same signals connected to the corresponding pins on the SCART connector. SID audio is mono, so the left and right channels are combined.

The signals of the S-Video standard (Chrominance, Luminance), give the best possible image quality, worse will be obtained from the integrated video signal (Composite Video).

But in general, the quality of the pictures depends mostly on the computer, the receiver and the quality of the cables used in the cable.

It is suggested to use a shielded cable (thicker rather than thinner), preferably with a separate shield for each signal.

We can classify cables into types, depending on which inputs we want to connect our equipment to.

DIN8U to SCART/EURO cables:

1. output the S-Video signal (Chrominance and Luminance) to the TV/monitor.

2. a Composite Video signal (integrated video signal) is output to a monitor or TV.

DIN8U to S-Video and/or RCA (Chinch) cables:

3. The TV/monitor receives its S-Video signal (Chrominance and Luminance) on a Mini DIN4 connector.

4. The signal to be sent is Composite Video on an RCA (Chinch) connector in yellow (this is the default).

5. Super cable, containing all possible signals on the proper connectors (S-Video and Composite Video).

Cables 3-5, can also be connected to receivers with SCART connectors via adapters.

It is important not to connect S-Video and Composite Video at the same time, as they can interfere with each other. Luminance and Compisite Video go into the same input on the SCART (pin 20). If audio is connected to a Jack input (e.g. 3.5mm), a suitable adapter can be used: 2xRCA (Chinch) to Jack.

If the image via the S-Video connector has a 'chequerboard' effect or too intense a colour, a resistor, usually 300-330 Ohm - ChromaFIX - can be connected in serial on the Chrominance signal. The resistor can also be adjusted (larger or smaller) to suit your Computer-Receiver combination. If you are not using the Audio In input, you can connect the SID's audio input (Audio In) to GND for a cleaner sound. This removes some noise that the SID from this input sends to the output. If our equipment has a SID (C64/C128), and we would like to use the audio input occasionally, another cable with a black RCA (Chinch) connector can be added (also the accepted way) if we have not previously connected this input to GND. The Audio In input is connected to pin 5 on the DIN connector.

Optionally, we can prepare a female connector without any wire, in which we internally connect the ground to the signal. Then, by connecting to the unused Audio In input, we will obtain a temporary ground connection and reduce the noise at the SID output. These cables do not require you to buy expensive DIN8U plugs (262 degrees) if you do not use the power supply (+5V pin-8). Some can be built on DIN5 (cable 2 and 4) or DIN8C 270 degrees (cables 1, 3 and 5). In the latter case, you have to remove the mismatched pins 7 and 8 (as shown in the photo).

The pins are easily removed if the base is fusible plastic, using pliers and a soldering iron. If the base is of other non-fusible plastic, cutting, drilling or pulling out. (C) 2023-2024